The present invention relates generally to voice call processing methods, and particularly to a method and apparatus for directing a phone call to a subscriber of an enhanced telephony product.
Recent technological advances have led to the dramatic decrease in the cost of telephony products such as mobile phones and pager services. As a result, the number of telephone numbers at which a particular individual may potentially be reached is rapidly increasing. For example, a typical individual may have a home phone number, several work phone numbers, a pager number, an answering service, voice mail and one or more mobile telephone numbers. While this multitude of telephony products is very convenient to the particular individual, it is often inconvenient for others to reach the individual because of the large number of possible phone numbers at which the individual might be reached.
To address this problem, many enhanced telephony services have been devised. Central to these enhanced telephony services is the concept of assigning a unique telephone number to each service subscriber. People wishing to contact the subscriber call the subscriber""s unique telephone number. Upon receiving a telephone call at the unique telephone number, the enhanced telephony service calls the numbers where the subscriber could potentially be located. If the enhanced telephony service is successful in locating the subscriber, the service directs the telephone call to the telephone number where the subscriber is located. To illustrate, a person (xe2x80x9ccallerxe2x80x9d) who wishes to contact a particular subscriber will telephone the subscriber""s unique telephone number. Upon receiving this call, the enhanced telephony service may poll the subscriber""s work telephone, home telephone, mobile telephone and/or any other telephone number that is listed in the subscriber""s personal profile until the subscriber is located. While the enhanced telephony service is polling the subscriber""s various telephone numbers, the caller is put on hold. Typically, at any time while the caller is on hold during this polling period, the caller may opt to be directed to the subscriber""s voice mail rather than wait for the enhanced telephony service to locate the subscriber.
In order to provide a valuable service, it is highly desirable that the polling period be minimized. Typically callers will not tolerate being on hold more than about thirty seconds. Therefore, the method used by the enhanced telephony service to locate the subscriber at one of the potential telephone numbers associated with the subscriber must be minimized. To minimize this polling period, several techniques are well known in the art. In a first technique, the subscriber periodically tells the enhanced telephony service the telephone number where he can be reached. A second technique is to have the subscriber provide the enhanced telephony service a schedule of where he can be reached. In a third technique, the subscriber provides the enhanced telephony service with the sequential order that the phone numbers associated with the subscriber should be tried. These techniques all have the disadvantage that they place a substantial burden on the subscriber. To be effective, they require at a minimum, that the subscriber inform the enhanced telephony service of possible schedule variances. Otherwise, the enhanced telephony service will not efficiently locate the subscriber and the polling period will become too long for callers to tolerate. In another well known technique, known as the shotgun or parallel search approach, all the phone numbers associated with the subscriber are called at once by the enhanced telephony service in order to locate the subscriber. The shotgun technique is advantageous because the subscriber does not have to provide the enhanced service provider with schedules or schedule variances. The shotgun technique, however, is disadvantageous because of the potential to disrupt people who share one of the subscriber""s telephone numbers, such as a spouse at home or coworkers at work, with a large number of telephone calls. Further, the shotgun technique uses ports in an efficient and wasteful manner. U.S. Pat. No. 5,793,859 uses a history database to avoid the inconvenience of techniques that require the subscriber to specify the telephone number where the subscriber is likely to be reached. The history database is used to calculate a statistical distribution that helps prioritize which telephone numbers in the subscriber""s profile are to be polled first. The history database tracks the success the enhanced telephony service has had locating the subscriber at each of the telephone numbers in the subscriber""s profile in the past. Typically, the history database is divided into time intervals, such as 7:00 AM to 8:00 AM on Mondays, etc. Thus, one record in the history database may, for example, track how often the enhanced telephony service was able to reach the subscriber at the subscriber""s home phone number between 7:00 AM and 8:00 AM. The enhanced telephony service uses the history database entry that corresponds to the time interval in which the enhanced telephony service received a call to prioritize or weight each of the telephone numbers in the subscriber""s profile. Telephone numbers that have a higher incidence of success, in terms of being used to successfully reach the subscriber, receive a higher priority or weight in the history database. The enhanced telephony service polls the telephone numbers in subscriber""s profile using the highest weighted telephone numbers first.
Although the use of a history database reduces the subscriber""s burden of providing information on where the subscriber is located at all times, the history database technique is ineffective at compensating for unexpected variances in the subscriber""s schedule. For example, if the subscriber is sick on a particular day or leaves work early, the history database technique will increase the amount of time it takes to locate the subscriber because the home phone number will be one of the last places the enhanced telephony service calls to locate the subscriber.
Each of the techniques used by enhanced telephony services to locate a subscriber has limitations. Further, the value of the enhanced telephony service is highly dependent on providing a minimal polling time. The longer the polling time, the less frequently the enhanced telephony service will be used because callers will attempt to reach the subscriber directly. Accordingly, there is a need in the art for improved methods for minimizing the average polling time required to locate a subscriber of a enhanced telephony service.
In summary, the present invention is an improved system and method for locating a subscriber to a telephony service at any one of a number of telephone numbers associated with the subscriber. In front-end embodiments of the present invention, a caller wishing to contact the subscriber places an incoming call to the subscriber""s unique telephone number and the call is directed by the telephony service. In back-end embodiments of the present invention, the caller places a call to the subscriber""s published or xe2x80x9creal phone numberxe2x80x9d, and if the number is busy or does not answer, the call is then routed to the telephony service, which then directs the call.
To properly direct an incoming call, the telephony service first attempts to reach the subscriber at the phone number that the telephony service reached the subscriber the last time an incoming call was routed to the subscriber. This last phone number is referred to as the Best Guess Location (xe2x80x9cBGLxe2x80x9d). If the telephony service is successful at reaching the subscriber at the BGL, the telephony service directs the incoming call to the subscriber at the BGL. Otherwise, the telephony service will use an alternative method to poll the remaining numbers associated with the subscriber. In some embodiments of the present invention, when the telephony service is successful at reaching the subscriber at one of the remaining numbers associated with the subscriber, the successful telephone number is automatically designated as the BGL. However, in a preferred embodiment, the subscriber is given the opportunity to designate the successful telephone number as the new BGL. This opportunity is provided even if the caller has abandoned the call before the subscriber has been connected to the caller.
In a preferred embodiment, when the subscriber receives an incoming call, the subscriber is given the option to transfer the call to one of the other telephone numbers associated with the subscriber or to a temporary ad-hoc telephone number that is not associated with the subscriber. If the transfer is successful, the telephone number the incoming call was transferred to can be designated as the new BGL. The reassignment of the BGL to the transferred telephone number may be limited to a fixed period, such as one hour, after which the system will revert back to the original BGL.
In another preferred embodiment, the telephony service only uses the BGL if one or more specific conditions are satisfied. If these conditions are not satisfied, the telephony service does not automatically try the BGL first. Rather, the telephony service immediately uses the alternate method for polling the subscriber""s telephone numbers. The specific conditions used to determine whether the BGL is to be attempted before alternative polling methods are invoked may include a time of day or date restriction, or an elapsed time cutoff. Thus, under a time of day restriction, if the last successful telephone call, which in some embodiments forms the basis for designating the BGL, was made before a predetermined time of day and the incoming call is made after the predetermined time of day, the telephony service uses an alternate method for locating the subscriber rather than first attempting the BGL.
In the present invention, there are several different possible alternate methods for polling the subscriber""s numbers if the BGL is not used first or was unsuccessful. In one embodiment, the subscriber specifies the order in which the subscriber""s telephone numbers are polled. In another embodiment, a history database is used to compute the likelihood that the subscriber is located at a specified telephone number at a particular time. The enhanced telephony service uses this information to poll the telephone numbers that have the highest likelihood of success.